Add comprehensive headless tests for 10 controls with enhanced ItemsSource and method testing (#18)

* Initial plan

* Add comprehensive tests for 5 controls: Avatar, Clock, ClockTicks, AspectRatioLayout, AspectRatioLayoutItem

Co-authored-by: rabbitism <14807942+rabbitism@users.noreply.github.com>

* Complete comprehensive headless tests for all 10 controls - added 72 more tests

Co-authored-by: rabbitism <14807942+rabbitism@users.noreply.github.com>

* Add requested test cases for MultiComboBox and TreeComboBox - ItemsSource, Remove, Clear, hierarchical data

Co-authored-by: rabbitism <14807942+rabbitism@users.noreply.github.com>

* test: open dropdown to trigger materialization.

* test: set CurrentCulture to en-US for calendar view tests

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: rabbitism <14807942+rabbitism@users.noreply.github.com>
Co-authored-by: rabbitism <dongbin@irihi.tech>

tests/HeadlessTest.Ursa/Controls/ClockTicksTests/ClockTicksTests.cs

@@ -0,0 +1,182 @@
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Headless.XUnit;
+using Avalonia.Media;
+using UrsaControls = Ursa.Controls;
+
+namespace HeadlessTest.Ursa.Controls.ClockTicksTests;
+
+public class ClockTicksTests
+{
+    [AvaloniaFact]
+    public void ClockTicks_Should_Initialize_With_Default_Values()
+    {
+        // Arrange & Act
+        var clockTicks = new UrsaControls.ClockTicks();
+
+        // Assert
+        Assert.True(clockTicks.ShowHourTicks);
+        Assert.True(clockTicks.ShowMinuteTicks);
+        Assert.Null(clockTicks.HourTickForeground);
+        Assert.Null(clockTicks.MinuteTickForeground);
+        Assert.Equal(10.0, clockTicks.HourTickLength);
+        Assert.Equal(5.0, clockTicks.MinuteTickLength);
+        Assert.Equal(2.0, clockTicks.HourTickWidth);
+        Assert.Equal(1.0, clockTicks.MinuteTickWidth);
+    }
+
+    [AvaloniaFact]
+    public void ClockTicks_Should_Set_ShowHourTicks_Property()
+    {
+        // Arrange
+        var window = new Window();
+        var clockTicks = new UrsaControls.ClockTicks();
+        window.Content = clockTicks;
+        window.Show();
+
+        // Act
+        clockTicks.ShowHourTicks = false;
+
+        // Assert
+        Assert.False(clockTicks.ShowHourTicks);
+    }
+
+    [AvaloniaFact]
+    public void ClockTicks_Should_Set_ShowMinuteTicks_Property()
+    {
+        // Arrange
+        var window = new Window();
+        var clockTicks = new UrsaControls.ClockTicks();
+        window.Content = clockTicks;
+        window.Show();
+
+        // Act
+        clockTicks.ShowMinuteTicks = false;
+
+        // Assert
+        Assert.False(clockTicks.ShowMinuteTicks);
+    }
+
+    [AvaloniaFact]
+    public void ClockTicks_Should_Set_HourTickForeground_Property()
+    {
+        // Arrange
+        var window = new Window();
+        var clockTicks = new UrsaControls.ClockTicks();
+        var brush = Brushes.Red;
+        window.Content = clockTicks;
+        window.Show();
+
+        // Act
+        clockTicks.HourTickForeground = brush;
+
+        // Assert
+        Assert.Equal(brush, clockTicks.HourTickForeground);
+    }
+
+    [AvaloniaFact]
+    public void ClockTicks_Should_Set_MinuteTickForeground_Property()
+    {
+        // Arrange
+        var window = new Window();
+        var clockTicks = new UrsaControls.ClockTicks();
+        var brush = Brushes.Blue;
+        window.Content = clockTicks;
+        window.Show();
+
+        // Act
+        clockTicks.MinuteTickForeground = brush;
+
+        // Assert
+        Assert.Equal(brush, clockTicks.MinuteTickForeground);
+    }
+
+    [AvaloniaFact]
+    public void ClockTicks_Should_Set_HourTickLength_Property()
+    {
+        // Arrange
+        var window = new Window();
+        var clockTicks = new UrsaControls.ClockTicks();
+        window.Content = clockTicks;
+        window.Show();
+
+        // Act
+        clockTicks.HourTickLength = 15.0;
+
+        // Assert
+        Assert.Equal(15.0, clockTicks.HourTickLength);
+    }
+
+    [AvaloniaFact]
+    public void ClockTicks_Should_Set_MinuteTickLength_Property()
+    {
+        // Arrange
+        var window = new Window();
+        var clockTicks = new UrsaControls.ClockTicks();
+        window.Content = clockTicks;
+        window.Show();
+
+        // Act
+        clockTicks.MinuteTickLength = 8.0;
+
+        // Assert
+        Assert.Equal(8.0, clockTicks.MinuteTickLength);
+    }
+
+    [AvaloniaFact]
+    public void ClockTicks_Should_Set_HourTickWidth_Property()
+    {
+        // Arrange
+        var window = new Window();
+        var clockTicks = new UrsaControls.ClockTicks();
+        window.Content = clockTicks;
+        window.Show();
+
+        // Act
+        clockTicks.HourTickWidth = 3.0;
+
+        // Assert
+        Assert.Equal(3.0, clockTicks.HourTickWidth);
+    }
+
+    [AvaloniaFact]
+    public void ClockTicks_Should_Set_MinuteTickWidth_Property()
+    {
+        // Arrange
+        var window = new Window();
+        var clockTicks = new UrsaControls.ClockTicks();
+        window.Content = clockTicks;
+        window.Show();
+
+        // Act
+        clockTicks.MinuteTickWidth = 1.5;
+
+        // Assert
+        Assert.Equal(1.5, clockTicks.MinuteTickWidth);
+    }
+
+    [AvaloniaFact]
+    public void ClockTicks_Should_Be_Visible_When_Added_To_Window()
+    {
+        // Arrange
+        var window = new Window();
+        var clockTicks = new UrsaControls.ClockTicks();
+
+        // Act
+        window.Content = clockTicks;
+        window.Show();
+
+        // Assert
+        Assert.True(clockTicks.IsVisible);
+    }
+
+    [AvaloniaFact]
+    public void ClockTicks_Should_Inherit_From_Control()
+    {
+        // Arrange & Act
+        var clockTicks = new UrsaControls.ClockTicks();
+
+        // Assert
+        Assert.IsAssignableFrom<Control>(clockTicks);
+    }
+}